Compensating device for gas operated firearms



Oct. 16, 1962 E. w. HAILSTON ETAL 3,058,400

COMPENSATING DEVICE FOR GAS OPERATED FIREARMS Filed Jan. 23, 1959 INVENTORS ELLIS W-HAILSTON ROBERT L.KELLY BvdA ATTORNEYS United States Patent Ofifice 3,@53,4fi Patented Get. 16, 1962 3,658,430 COMPENSATING DEVHCE F012. GAS OPERATEE FWsEARMS Ellis W. Hailston, Ilion, and Robert L. Kelly, Cooperstown, N.Y., assignors to Remington Arms (Iompany, Inc, Bridgeport, (Conn, a corporation of Delaware Filed Jan. 23, 1959, Ser. No. 788,540 2 Claims. (Cl. 89-193) This invention relates to firearms of the type which .utilize the explosion gases of a fired cartridge to operate the breech mechanism, which usually involves extracting the fired cartridge from the chamber, cocking the firing mechanism, and feeding the next cartridge from the magazine into firing position in the chamber.

Modern firearms, particularly those in the shotgun category, must be able to operate satisfactorily and reliably on ammunition which varies widely as to power of the propellant charge or load. Ammunition available varies from the very high pressure and velocity charge through a medium range to a low limit. Particularly in shotgun shooting, the selection of an ammunition type as to power of charge may depend on the desires of the shooter and the type of shooting activity engaged in. The range of cartridge power loads has expanded upwardly into the magnum type charges and downwardly into the light charges as are used in skeet and trap shooting to a degree which causes improper operation or failure of conventional gas operated guns in the extended power load ranges. With certain types of guns the present light power loads do not have enough energy to completely actuate the breech operating mechanism which causes jams and other operational defects such as failure to extract and eject. In other types and perhaps the same types of guns, available heavy or high power loads apply too much energy to the breech operating mechanism in a violent action which slams parts such as the slide and breech bolts to the rear with sufiicient force to cause breakage and other improper results such as the extractor pulling through the cartridge rim, or pulling the metal head from cartridge body. Attempts to add strength to parts .to handle the high power loads usually result in changes which render the firearm mechanism less likely to function properly with the light or medium power loads. It is recognized as highly desirable to the shooting public for the provision of firearms which possess the maximum flexibility in use and choice of cartridge power load.

It is an object of this invention to provide an improved gas-operating mechanism for firearms which automatically compensates for the ammunition power load used so that a single mechanism can safely, satisfactorily and automatically handle the full range of loads from light to heavy without manual adjustment or likelihood of damage to the firearm.

It is another object of this invention to provide an improved gas system for operating a firearm which functions as indicated in the preceding paragraph and is simple and economical in construction yet effective and reliable in operation.

It is another object of this invention to provide an improved automatically compensating gas operating mechanism which requires a minimum of cleaning and maintenance.

It is another object of this invention to provide an improved gas operating mechanism as aforesaid which does not direct the escaping gases from the mechanism on the shooters hands as is the case in guns which allow the gas to escape in the vicinity of the magazine cap at the forward end of the fc-restock. This escape of the gases is a problem to numerousshooters who actually grasp the forward end of the forestock and magazine cap to obtain maximum torque in swinging the gun at high lateral deflection rate targets.

Other objects and advantages will appear from the detailed description of the following specification, the accompanying claims and the drawing in which:

FIGURE 1 is a fragmentary longitudinal vertical cross sectional view through a portion of the barrel and gas operating system of a firearm embodying features of the present invention with the parts shown in the rest or equilibrium position. The forestock is not shown.

FIGURE 2 is a similar view to that of FIGURE 1 with the parts shown in positions they would take upon the initial rearward shock of firing before the shot or projectile and propellent gases have reached the gas passage through the barrel. I

FIGURE 3 is a transverse sectional view taken on line 33 of FIGURE 1.

The firearm shown in the drawings is, except for the improved gas operating system, generally similar to such conventional firearms as are illustrated and described in considerable detail in co-pending patent application Serial No. 582,153, filed May 2, 1956, now Patent No. 2,941,- 450, in the name of Lexie Ray Crittendon et al. The firearm shown in the accompanying drawing comprises a barrel 1, which is provided with the usual base and chamber and is rigidly secured to a receiver (not shown). Mounted beneath and parallel to the barrel 1 is a magazine tube 4 which is also rigidly secured at its rear end to the receiver (not shown). The receiver contains the usual breech mechanism comprising a breech bolt and a firing mechanism. The magazine tube 4 houses the usual magazine follower and follower spring (not shown), the latter abutting at its forward end a stop in the magazine tube. A breech closing spring 15 is housed in the forward portion of the magazine tube with its rear end abutting the follower spring stop and its forward end abutting slidable frame element 30. A barrel guide element 2 is secured to the barrel 1 in position to embrace the forward gas cylinder end of the magazine tube when the barrel is secured to the receiver. The barrel 1 is secured to the receiver by magazine cap 5 which threadably engages the magazine tube 4 and bears against the forward face of barrel guide element 2.

A wooden forestock (not shown) generally encloses the magazine tube and closes the gap between the magazine tube and the barrel.

As will be understood by those skilled in the art, the breech bolt assembly (not shown) is mounted for longitudinal reciprocation. The breech bolt assembly is connected to slidable frame element 30 by two longitudinally extending action bars (not shown) which join to form a single longitudinal connecting member or linkage 17 which in turn is connected to element 30 by a formed rivet 16 extending through a longitudinal slot in magazine tube 4.

Frame element 30 may be of any convenient form and configuration within the requirements of providing sufficient bearing relationship to the interior of magazine tube and adequate strength to handle the stresses carried thereby. The preferred embodiment of element 3% as shown in the drawings is a cup-shaped structure having opposed bearing surfaces 31 and 32 aligned with the main portion of the linkage 17 to prevent rocking or chattering action in its movement in the magazine tube and also provided with substantial clearance between its periphery and the interior of the magazine tube at the sides thereof for free flow of gas about it (FIG. 3). Apertures 18 may be also provided in the end portion of element 30 to prevent or reduce any dash-pot effects of air trapped between the parts. Element 30 could conveniently take the form (not shown) of a three or more legged spider ele 3 ment connecting longitudinal member 17 with gas piston element 7.

A connecting rod is slidably received in an axial passageway through the transverse end portion of element 30. Threaded on the rear end of rod is a nut or other enlarged abutment member 13. A compression spring 14 is positioned around rod 10 and acts between the transverse end portion of element 30 and the nut 13 to urge the abutment and rod 10 rearwardly. Suitably secured to the forward end of rod 10 is a gas piston element 7. As can be seen from the drawings, the gas piston 7 and element 30 are resiliently urged together by spring 14. Thus, it can be seen that a lost motion assembly exists between piston 7 and element 30. This assembly consists of rod 10, member 13, and spring 14. Gas piston 7 is provided with a rearwardly extending annular skirt portion 12. Gas piston 7 is provided with an annular gas Seal and bearing shoulder 11 on its exterior cylindrical surface. Intermediate its ends, gas piston 7 is provided with an annular cut-away portion or groove 8. Intersecting annular groove '8 is a plurality of axial passageways 9 which connect the forward end surface of the gas piston with the annular groove. The gas piston 7 and its shoulders provide a close sliding fit in the interior of the magazine tube. The parts are so proportioned and assembled so that in their rest or equilibrium position, with the breech bolt assembly in its forward breech closed position, the annular groove 8 is positioned adjacent the opening of the gas passage 3 connecting the bore of the barrel with the interior of the magazine tube as shown in FIG. 1. The parts are in this FIGURE 1 position at the instant before the firing of a cartridge in the chamber of the barrel.

It has been observed that the recoil impulse on firing a gun commences before the projectile or shot can move an appreciable distance along the barrel and well before the projectile or shot leaves the muzzle.

The characteristics of spring 14 are selected so that at the initial rearward recoil impulse of the gun, including parts 17, 16 and 30 which are locked to the breech block, all of these gun parts move to the rear leaving the gas piston 7 substantially in its initial position due to its inertia. This action tends to separate gas piston 7 from frame element 30 against the action of spring 14 as shown in FIGURE 2. This relative movement of gas piston 7 under the influence of the initial recoil force alone, occurs before the shot and gases have reached the gas port 3 in the barrel. This relative movement causes the annular groove 8 in the gas piston 7 to move forwardly away from its rest position adjacent the gas port in a direction to close off the gas port 3. When the moving shot and gas column reach the gas port 3 an amount of gas controlled by the amount of closure of port 3 by piston 7 will be admitted to the interior of magazine tube to force piston 7 rearwardly into abutment with element 30 to operate the breech against the action of breech closing spring 15. When the annular groove 8 moves far enough to the rear the trapped gases are exhausted through slot 35 to escape along the forestockbarrel intersection. As the gas pressure acting on piston 7 subsides and the breech assembly reaches its rearward limit of movement, the breech closing spring asserts itself to move the breech assembly and connected gas piston structure back to the rest position shown in FIGURE 1. The characteristics of spring 14 can be selected so that the metering action will take place on portclosing movement of the piston or on port-opening movement after complete closure of the piston. The latter method is preferred.

It will be clear to those skilled in the art, as well as others, that the amount of separation of gas piston 7 from frame element and hence the amount of closing off of the gas port 3 by the gas piston will be proportional to the initial recoil impulse independent of the later action of the propellent gases on the system. The amount of closing off the gas port 3 by the piston 7 will control the amount of gas allowed to act on the piston 7 and breech assembly. The heavier the cartridge load the larger the initial recoil impulse and the more the inertia affected piston will close off the gas port. Conversely, lighter cartridge loads will cause a smaller initial recoil impulse and less gas port cutoff at the time the gases reach the port. It follows that on the heavier loads the gas port will be substantially closed off by the piston during the substantial portion of gas flow and less gas will be metered through the port to operate the breech mechanism. On lighter loads the gas port will be proportionally more open during the substantial portion of gas flow and more gas will be metered through the port to operate the breech.

Another way of looking at the operation of the parts is in terms of the time required for the piston 7 to return to the full open position with respect to the port 3 compared with the time required for the shot and propellant gases to reach the gas port. When the heavier loads are fired the initial recoil of the gun and inertia eifect on the piston element is greater than for lighter loads. Consequently the piston element does not recover as rapidly from its inertial port-closing surge so that total elapsed time for the piston to return to its open port position is proportionally greater for heavy loads than for light loads. In addition, the heavy loads propel the shot and gases up the bore with a higher velocity which means that the gases reach the port sooner as well as expend its energy out the muzzle sooner. Combining these effects it will be understood that on heavy loads the gases will reach the port while the port is still closed or substantially closed by the piston, and before too great an effect can be applied to the piston, the gases are exhausted from the muzzle which effectively holds the forces acting on the entire gas operated system to safe magnitudes. Conversely more gas is available for a longer interval on the light loads to insure that proper operation will occur.

The novel compensating features of this invention operate to delay and restrict the flow of gas to the piston chamber in proportion to the energy content of the load being fired.

While a specific preferred embodiment of this invention has been described, it will be understood that other modifications will be apparent to those skilled in the art yet properly within the scope of the appended claims.

What is claimed is:

1. A compensating device for a gas-operated self-loading firearm for firing cartridges with propellant charges of varying energy content comprising, a barrel, a gas cylinder secured to said barrel, a gas passageway connecting the interior of said cylinder with the interior of said barrel, a gas piston slidably positioned in said cylinder, an annular groove in said piston positioned adjacent said passageway, at least one axial passageway in said piston connecting said groove to the forward end of said piston, an annular skirt formed on the rear of said piston and engaging a slidable frame positioned in said cylinder, a rod passing through said frame and having one end secured to said piston and an enlarged opposite end, a spring on said rod positioned between said enlarged end and said frame, whereby said piston has relative forward longitudinal inertial motion in one direction to thereby vary the opening of said passageway and restrict the flow of gases from said barrel to said cylinder in proportion to the energy content of a fired cartridge.

2. A compensating device for a gas-operated self-loading firearm of the type capable of firing cartridges with propellant charges of varying energy content comprising, a barrel having a bore, a gas cylinder secured in position adjacent said barrel, a gas passageway connecting the bore of said barrel with the interior of said cylinder, a gas piston slidably received in said gas cylinder, said piston having an annular groove adjacent said gas passageway and a plurality of axial passageways between said 5 6 groove and the forward end of said piston and an annu- References Cited in the file of this patent lar skirt on the rear end thereof, a lost motion assembly UNITED STATES PATENTS connected to said piston, said assembly being a frame member slidably received in said gas cylinder and en- 2 L Smlth 14, 1919 gaging said skirt, a rod connected to said piston passing 5 MacGfegol' a 1937 through said frame and having an abutment on the op- 2,451,624 at 19, 1948 pOsite end thereof and a spring surrounding said rod 214821880 Sefned p 27, 1949 between said frame and said abutment, said assembly per- 218141972 511111110115 3, 1957 mitting limited forward longitudinal inertial movement 2:365255 Marsh 23, 1958 of said piston in said cylinder relative to the gas passage- 10 2,902,903 Browning p 8, 1959 way opening to delay and restrict the flow of gases from said bore to said cylinder in proportion to the energy content of a fired cartridge. 

